The invention relates to an open end friction spinning machine with a plurality of adjacently arranged spinning units which respectively incude two adjacently arranged friction rollers driven in the same rotational direction and forming a wedge slot to which single fibers of opened fiber material are fed from a feeding and opening device and in which slot these fibers are twisted together to form a yarn which is drawn off by a withdrawal device.
Inside the spinning units of open end friction spinning machines, and especially in the region of the friction rollers, there can occur an accumulation of fiber fly, fiber residue, fiber dust, or other contaminants of the fiber material. These contaminants can also adhere to the outer surface of the rollers and during the course of time lead to a deterioration of the spinning results. It is therefore necessary to clean the rollers from time to time, and especially after a yarn break. In order to facilitate this cleaning, it is already known (EP-OS No. 52 412) to support the two rollers independently from one another so that they can be movable away from one another to expose the wedge slot, whereafter a manual cleaning can take place. Because the exact maintenance of the dimensons of the wedge slot is an important prerequisite for uniform spinning results, this arrangement requires a very expensive bearing construction to facilitate movement of the rollers with respect to one another. Furthermore, it is undesirable to have cleaning carried out by hand by a maintenance person because the cleaning process becomes dependent upon the care of such servicing person.
The invention is based upon the problem to design an open end friction spinning machine of the above-mentioned kind with which an automatic cleaning of the rollers can be carried out.
This problem is thereby solved in that a mobile servicing unit or cart is provided which is movable in the machine longitudinal direction and which is adjustably movable to respective spinning units to clean the friction rollers.
With the arrangement of the invention it is achieved that the cleaning of the rollers is not dependent on a servicing person and is therefore independent of the carefulness of such person in carrying out the cleaning process. It can further be provided according to preferred embodiments of the invention that the cleaning process is carried out in conjunction with operational interruptions at a spinning unit which occur in any event; for example, after a yarn break or during a yarn spool change. In certain preferred embodiments, it is provided that the servicing cart is outfitted with a detection device which detects the operational interruption and stops the cart at the affected spinning unit and carries out a roller cleaning operation. However, it is also provided in certain especially preferred embodiments that the cleaning apparatus of the servicing cart preventively clean the rollers of the individual spinning units from time to time, such as after a certain running time of the corresponding spinning unit, after a certain yarn volume, and after detection of deteriorating yarn quality by means of an auxiliary yarn quality detecting device.
According to one arrangement of the invention, each spinning unit is provided with respective cleaning elements arranged at the rollers. These cleaning elements are held in an out-of-operation position by preferably spring loaded return elements and are adjustable to an operational mode to clean the rollers by means of activating elements on the servicing cart. With this arrangement, each spinning unit is provided with its own cleaning elements so that the servicing cart itself can be very simply and economically constructed. This arrangement also exhibits the advantage that the servicing person, during a servicing operation such as start spinning, can carry out a cleaning by activating the cleaning elements of the spinning unit without waiting for the servicing cart. With these arrangements, one can advantageously arrange the cleaning elements at positions of the spinning units which are not readily accessible as long as the devices necessary for engaging with the activating elements of the servicing cart are readily accesible.
According to another arrangement of the invention, the servicing cart is provided with cleaning elements which are adjustably movable to the rollers of the respective spinning units. In this arrangement the servicing cart is then certainly in its construction somewhat more expensive than with the arrangement mentioned in the preceding paragraph. However, this arrangement avoids the necessity to have cleaning elements provided at each of the many spinning units. Furthermore, this arrangement is advantageous in that the functioning of the cleaning elements can be centrally supervised at the servicing cart so that also only a small number of cleaning elements are required that must be repaired or replaced.
In advantageous arrangements of the invention it is provided that the servicing cart includes an adjustable roller shaped cleaning brush which is movable to the yarn forming wedge slot between the two friction rollers of a spinning unit. With such a cleaning brush arrangement it is possible to carry out a very efficient cleaning with only a single brush being necessary because it can be adjustably moved into the region of the wedge slot to engage the surfaces of both friction rollers. In especially advantageous embodiments the roller shaped cleaning brush is disposed inside of a pot shaped cap or hood which engages with its rim at a housing for the rollers of the spinning unit. This hood is advantageously connected at an underpressure (vacuum pressure) source of the servicing cart. The loosened contaminants or fiber remains or the like are then immediately sucked off with the hood enclosure preventing that these contaminants travel to another position of the spinning unit or of the machine.
In further arrangements of the invention it is provided that the servicing cart is provided with at least two suction nozzles which are adjustably movable to the rollers of the respective spinning units. These suction nozzles facilitate the removal of contaminants from the regions of the rollers which are not readily accessible to a cleaning brush.
In certain advantageous preferred arrangements of the invention, the servicing cart is provided with at least two blast (pressurized air) nozzles which are adjustably movable to the rollers of a spinning unit. Especially in conjunction with the suction nozzles, these blast nozzles are advantageous because then contaminants also in the inner regions of the roller are loosened and can be removed. Because it also can occur that the contaminants are relatively fixedly adhered to the coating surface of the rollers, it is provided in further arrangements that the servicing cart is provided with at least two scratch bars or doctor blades which are adjustably movable to the rollers of a spinning unit. With these scratch bars/doctor blades, the fixedly disposed or adhered contaminants can be loosened, separated and removed.
In advantageous arrangements of the invention, it is provided that the cleaning elements of the servicing cart are arranged at a cleaning head which is adjustably movable to respective spinning units. Such an arrangement accommodates a collection of the cleaning elements together which also facilitates their common effectiveness. Furthermore, the constructional expenditures, especially for the adjusting devices, are made smaller by providing several cleaning devices at a single cleaning head. In especially advantageous embodiments at least one guide element is provided at each spinning unit, against which guide elements the cleaning head is disposed and aligned via an abutting counter piece at the cleaning head. It is assured with this arrangement that the individual cleaning elements are exactly aligned with respect to the rollers so that they can carry out their full effectiveness. Furthermore, there are no unnecessary high tolerances required for the arrangement of the individual spinning units because the cleaning head is automatically aligned upon the adjustment against the spinning unit.
In further arrangements of the invention the servicing cart is provided with an adjustable driving device for the rollers to be cleaned at the respective spinning units. With this construction, the driving of the roller during the cleaning is facilitated with the rollers in a servicing mode disconnected from their normal operating drive. The drive via the servicing cart can then be carried out with suitable predetermined rotational speed which are optimal for cleaning, as well as with reverse rotation of the rollers to facilitate cleaning of the rollers. In situations where a cleaning process is to be carried out, without means at the spinning unit for transferring the rollers themselves to an interrupted drive maintenance position, the servicing cart is advantageously provided with a device for interrupting the drive for the rollers of a spinning aggregate or unit.
Further objects, features, and advantages of the present invention will become more apparent from the following description when taken with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.